Strange Network Problem

For some strange reason I can't have both the xbox connected and the internet connected at the same time. I have two network cards and they both work perfectly fine indevidually, but when I turn on the xbox 90% of the time it makes the internet stop working. As you can see, that makes it pretty hard to use xbconnect. The strangest part of it is that it doesn't do it every time, just Most of the time, and when the internet isn't working the computer still indicates that it is working perfectly fine. Any help anybody can offer would be appreciated.

P.S. I tuned off all firewalls and it didn't make a difference, and compatibility scans come clean

For some strange reason I can't have both the xbox connected and the internet connected at the same time. I have two network cards and they both work perfectly fine indevidually, but when I turn on the xbox 90% of the time it makes the internet stop working. As you can see, that makes it pretty hard to use xbconnect. The strangest part of it is that it doesn't do it every time, just Most of the time, and when the internet isn't working the computer still indicates that it is working perfectly fine. Any help anybody can offer would be appreciated.

P.S. I tuned off all firewalls and it didn't make a difference, and compatibility scans come clean